class Cylinder:
    num = 3.14
    def __init__(self,a,b):
        self.r=a
        self.h=b
    def volume(self):
        r=float(self.r)
        h=float(self.h)
        self.v=r*r*h*Cylinder.num
    def print(self):
        print(self.v)
a = input("请输入圆柱体的半径: ")
b = input("请输入圆柱体的高: ")
c1=Cylinder(a,b)
c1.volume()
print('圆柱体的体积为:',end='')
c1.print()